Cycle News is a weekly magazine that covers all aspects of motorcycling including Supercross, Motocross and MotoGP as well as new motorcycles
Issue link: https://magazine.cyclenews.com/i/127651
HONDA NSR500 NSR500 chassis for '93, which was to alter the design of the rear shock mo unting? Doohan and the other Honda riders had handling problems in the early part of the season in spite of that, with the bike wanting to run wid e through comers rather than turn and hold a tight line, as it had done so brilliantly in '92. Doohan ditched the new 16.5-inch deeper sidewall Michelin tire - which may, perhaps, have been the culprit - and after that the bike turned better. At Suzuka it was noticeable how much more responsive and d irect-steering his bike was compared to Criville's, albeit at reduced speeds because of the damp track. HRC's 500cc technical boss Hattorisan pinpointed the reason for the big difference in handling between the two bikes when I taxed him . "Criville-san likes very hard suspension settings, especially on the forks, because he likes to brake very hard and late into turns, and doesn' t like the forks to d ive, so tha t he gets maximum front tire gri p," he said. "He also uses a wider head angle than Mick-san's bike, to try to increase stability .und er braking and p reven t the front w heel tucking und er w hen he turns into the comer." Well, okay - but this sounds like a recipe for understeer, as well as the heritage of a former 12Sec World Champion's riding style, pe rhaps a clue as to why such a brilliant rider as Criville has struggled to really get on the pace consistently in 500cc racing . This season, when he races un der HRC's direct umbrella, he may be persuaded to change. As it is, Doohan's bike is notably quicker in steering and easier to ride, without being twitchy or sacrificing st ability - and I was on his dry wea ther settings, remember? The s to p ping p ow e r o f the twi n 290mm Bremb o carbon brakes fitted to the NSR is aw esome, but it takes some coming to terms w ith because the ir potential is so much greater th an the metal d iscs the rest of us mere mortals have our thought processes and reaction times conditioned to using. An idea of the sensitivity the black brakes now have can be gauged by th e fact that Honda even uses them on a wet track, as they did for my Suzuka test, provided the ambien t temperature is anywhere above arctic conditions - or Britain in sp ringtime. The shrouds help main tain op tim um operating temperature of 400600 d e grees Ce lsius, of cou rse, b ut an other factor is the slim mer thickness of the rotors, themselves, which he lps them stay hotter longer. H onda uses 320mm d iscs for so me twisty tracks, but even then Doohan still . likes to use the rear brake very hard, a relatively uncommon hab it among mod em GP racers and one he found ha rd to live with at the start of las t season. Thanks to his injured right leg, he found it impossible to lift his foot off the pedal as he cranked into a right-hander, which robbed the bike of precious horsepower because he was dragging the brake all through th e corner. Yet it ga ve new meaning to the term "rear wheel steering", too ! By Jerez, the team had concocted a hand-operated brake lever on the left handlebar, similar to a Jet Ski throttle (he shou ld be used to one of those), which you operate with your left thumb as you use the fingers on the same hand to hold the clutch while you shift down the gearbox. Honda then removed the foot brake altogether, bu t put it back on for my test. They needn't have bothered, because I never use the rear brake - obviously another black mark against my suitability as a works NSRSOO rider - so it was quite difficult to judge the effectiveness of the system. Even though your left hand gets a little busy, I can see how it would work. I wonder if Doohan will retain it next season when, hopefully, his leg will be back in normal service? When all's sai d and done, Honda's trump card is still that fantastic engine so powerful yet so tractable, so eager for revs, yet so smooth in delivery. In spite of the extra ma ss of the single cra n kshaft, it picks up engine speed almost faster than your e ye can read the tachometer, .pulling cleanl y off the bottom of the powerband at 8500 rpm with a completely smooth, linear d eli very and a punch which even the World Champion Suzuki can't rival. But there 's more. Criville's bike had an astonishin g amount of over-rev, running way pa st the 12,500 rpm peak power mark without any noticeable fall-off in the power delivery. Cobas told me afterwards that Criv- ille shifts up normally at 13,800 rp m in the gears, and regularly uses over 14,000 rpm to save a pair of gearchanges wh en he has to. I can see after ridin g the NSR in the dry how this would be possible, meaning that Honda's w in ter work on the' engine didn't on ly incl ude ge tting more power and improving carburation - they also added more revs to an engi ne which p reviously topped out at a little over 13,500 rpm. You couldn't imagine a grea ter contrast with the works Yamaha I tested , which d idn't really want to rev a lot higher than 13,000 rpm, and had a narrower effective powerband . Yet, in spite of this, HRC boss Yoichi Oguma says that one of the Honda engineers' greatest successes has been ,in extending the component life and reliability of the engine, mostly by using new materials, but also w ith new engineering techniques. "To ge t the NSRSOO machine to the first race o f th e season is very, very expensive," says Oguma, "but after that, it's cheap! Our engineers have made big steps in increasing th e safe mileage of engine parts - the NSRSoo p istons w ill now last 500 km (310 miles), for example, and cr anksha ft life is also much higher. This is important in reducing the overall cost of GP racin g, which in these difficult economic times, is a main concern." All those revs, and ye t imp roved component life? Amazing ... About the only thing I didn't like on either NSR was the ge ar change. Both gearboxes see m ed ra th er harsh and mechanical, just like a Cagiva's always has been . This may well be an inevitable downside of all that power the engine's now producing, requiring the dogs on (Right) The major change to the '93 Honda was to move the air Intakes to the flanks; In '92, the Intakes came directly from the nose of the fairing. (Below) Doohan's Jet-Ski type rear brake lever. each pinion to be undercut more to keep in mesh. It may also explain why Honda is the last of the 500cc GP teams to fit a spee d-shifter. The design of the gearbox is very complex say those who work on the bikes, presumably a function of hav- ing to harness all that power without giving too much away in weight. Honda does have a sys tem under development, but Hattori says Doohan doesn' t feel the need for such a quick-changer just yet, so they're not fast-tracking it. So there... Instead, Honda is fas t-tracking its fuel injection system, and it's almost certain that all the works NSRSOOs, including the Team Pons bike of Alberto Puig, will be fitted with EFI by the start of the '94 season. " It is undesirab le and costly to race w ith both fue l-injection and carburetor m ach ines at th e sa me time," says Oguma. "And I think it is confusing for team mechanics to work on two different kinds of engine. So, we mu st d ecide before th e s ta rt of the comi ng se as on whether we will use only carburetors or only fuel injection on our 1994 NSRSoo machines." Any bets on which way the decision will go? CN